High precision operational amplifiers are used in differential amplifier circuits to achieve a high level of accuracy in applications where sources of error such as offset and gain errors, noise, tolerance and drift must be minimized. In addition resistors in amplifiers must also have identical ratios (R2/R1 = R4/R3) — such as those found in the LT5400 quad matched resistor network or the LTC6363, for an option with integrated matched resistors on the chip— to avoid a common-mode error. In this article from Analog Devices, you can learn more about the ability of a differential amplifier to reject a common-mode error in terms of the common-mode rejection ratio (CMRR).
How Precisely Matched Resistor Networks Increase the Common-Mode Rejection Ratio of Differential Amplifiers
18 Feb 2019